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Cayenne Turbo Brass T Pipe Mod

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Cayenne Turbo Brass T Pipe Mod

Hi My car already had the aluminium coolant upgrade, but the famous "T" pipes went blew the other day. There is already two excellent tutorials on replacing the cooling pipes and the "T"'s but I wanted to go one better and replace the aweful stupid plastic "T"'s with something that hopefully will outlast the car itself. Firstly you'll need to remove the plenum chamber, to get to the hoses, this is covered in detail in the other tutorials. We will be replacing/upgrading 3 troublesome plastic


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  • 3 weeks later...


Great post! I have a leak high in back on a rubber to metal line that I will probably have to get at by pulling the intake. When I go in I will do what you have done as well. Any idea what size the T brass? You guys metric so maybe tricky for U.S. local to get right size. I am assuming that you replaced the rubber as well since it was in little pieces.

Thanks again,


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  • 3 months later...

Hi Everyone.

I've had a few questions from people about the sizes of the "T".

The big one (which has the 25-16-25 mm outlets) is 75mm from end to end between the big outlets.

My brass one was a bit longer than that, probably about another 10mm.

You don't have much room to move back there so you can't go much bigger than that.

The guy at the hose shop was able to fabricate it using a standard 3 way 25mm brass T, cutting off the middle outlet, and then cutting the outlet off a 3 way 16mm T. He then tapped it in and brazed the small outlet in.

The smaller "T" is a standard off the shelf 16mm 3 way. Cost me about 8 bucks.

I tried making the 25-16-25 "T" from brass screw fittings, but the resulting "T" was way too big to fit in.

I also purchased new assemblies from Porsche to replace the rubber hoses, due to having to destroy them to get them off.

I'm happy to report that after 5 months, the repair is still perfect, and withstanding 38oC days (that about 100oF in the "old money") with zero loss of coolant.

I hope that helps!

Edited by darrinsmith
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  • 3 weeks later...

Absolutely brilliant! Wish I had thought of this a few years ago when I did mine - though I'm heading back in there this week for a different (?) leak... tempted to do the upgrade since it's all sitting right out in the open anyway. That big tee is a royal pain though.

For anyone with a Turbo doing the coolant pipe fix to aluminum - you have to do those tees anyway. This mod is some serious insurance that you will never have to delve into that dark corner of the the nether-region ever again.

Darrin - if you got your guy to source them and ship them out fast, you could make a lot of people happy. And maybe fund some other hobbies.

Well done!!

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  • 2 weeks later...
  • 3 months later...


I must apologise, I have made a typo with the size of the little "T" it should be a 16mm all round.

The big "T" is definitely 25-16-25.

I have will edit the original post to correct the error.

If you're going to do this fix however, I recommend you order the new hoses and assemble/fabricate your replacements before you disassemble the car, to make sure you get the sizes correct and to minimise your down-time.

I didn't check the size of the little vacuum "T" but I sourced it no problems from the local auto store. It is the same size all around, if I could buy it here in Perth Western Australia (aka Wait Awhile or "what a Porsche, no we don't have anything that'll fit that"), then I'm sure you can get something to suit at your local auto store!

All the Porsche hoses are metric, so all you Imperial people will have to make do with what you have, fortunately the differences shouldn't be too much of a problem compared to a bolt size/thread type.

Thanks and sorry to all....



Edited by darrinsmith
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  • 8 months later...

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